UWB Compact Microstrip Patch Antenna with High Directivity Using Novel Star-Shaped Frequency Selective Surface

Abstract

This paper presents a single element ultra-wideband (UWB) microstrip patch antenna with high directivity. In this work, techniques like partial ground and modification of the patch have been used to achieve the UWB. The designed antenna consists of a modified U-shaped radiating patch with a microstrip feed attached directly to it. The initial U-shaped radiating patch is modified by attaching an inverted trapezium on both sides of the feed line. Two parasitic patches are introduced near the feed structure of the antenna after etching away two rectangular slots with appropriate dimensions. Moreover, the proposed structure consists of a partial ground plane which contributes to the UWB nature. Modifications in the form of square and triangular slot etching are carried out in this part of the proposed structure. The proposed antenna is compact with dimensions of 16 mm×19 mm×1.6 mm. Finally, gain enhancement of the proposed structure is done by placing a Frequency Selective Surface (FSS) behind the proposed antenna with an air spacer in between the structures. A novel FSS unit cell is proposed, and its performances are checked experimentally. Later, FSS is combined with the antenna, and measured peak gain of 9.7 dBi is obtained experimentally. The overall size of the structure is 62.5 mm × 52 mm × 24.9 mm.